Sk Hynix reports that it has developed a 512Gbit nandflash based on 176 layers. According to the Korean chip company, the chip leads to lower costs for nand memory and enables higher throughput rates.
It is the third generation of nandflash memory that SK Hynix produces under the name ‘4D’. In 2018 the manufacturer started with this type of memory, then with 96 layers to get to 512Gbit and last year 128-layer nandflash followed. Compared to that generation, the 176-layer successor would offer a 20 percent higher speed when reading the memory cells.
The throughput of the new memory would increase by 33 percent over the previous generation, to a total of 1.6Gbit / s. SK Hynix wants to start production of the memory for smartphones and other mobile products halfway through next year, after that the consumer market for SSDs and the enterprise market should follow. The larger amount of layers increases bit productivity: the company can extract more memory from wafers, which can reduce costs.
SK Hynix uses the marketing name 4D to designate 3D-nand based on charge trap flash with periphery under cell technology. With periphery under cell, the company places the control logic of the memory cells under the nand, which increases the density. As the number of layers of memory cells increases, it becomes more difficult to drill holes through the layers, SK Hynix further reports. The company has therefore made the interlayers as thin as possible, but this in turn can lead to interference. To maintain performance and reliability, SK Hynix applies various techniques, including adjusting the stresses based on the properties of the layers.